PORT CLINTON, Ohio — Closing arguments are set to begin Monday in the case of Scott Speer, who is accused of killing his best friend by pushing him over the side of a boat into Lake Erie.

Speer, 42, is accused of killing James Barnett, 39, near Mouse Island on Aug. 6, 2002. The two had been friends since they were teenagers, and Barnett was working for Speer at his plastics company. (MAP)

Speer is charged with murder, aggravated murder, aggravated vehicular homicide and involuntary manslaughter, although a judge said Friday that he had serious questions about whether there was enough evidence to support a charge of aggravated murder.

Speer's defense had asked for the charges to be dismissed.

"I'm going to deny the motion at this time, but I'm telling counsel if there is a verdict on that issue, I may wish to reconsider," Judge Richard Markus said.(VIDEO)

Story continues

The prosecution's key witness, William Seese, testified last week that Speer had confessed to him in the summer of 2003 that he pushed Barnett off the boat. But Speer's lawyer, Russell Buzzelli, argued to Markus that Seese never said whether the push was on purpose or accidental.

Seese admitted using Vicodin the day of the alleged confession, but insisted that he remembered the conversation clearly.

A private detective hired by the defense to interview Seese testified Friday that he felt Seese exhibited the classic behavior of someone who had taken numerous opiates.

Andrew Kasarda, who worked for more than 27 years with the Akron Police Department before becoming a private detective, said Seese initialed a document indicating that his statements were untruthful.

"[Seese] basically said he said it because he thought he could make the statement, make the police happy and they would leave him alone," Kasarda said referring to the alleged confession.

Barnett's family has said he was set to testify against Speer in his upcoming divorce proceedings, but the prosecution rested its case without introducing any evidence of that motive. Seese's testimony, therefore, is the only evidence prosecutors presented for the aggravated murder charge.

In his defense case Friday, Speer's lawyer also called Gregory Group, a certified marine surveyor, to contradict a prosecution witness who testified that Speer must have been speeding recklessly in rough waters the night Barnett went overboard. Group said he believed it was impossible to calculate how fast Speer was driving.

"I found that it was and is impossible to retroactively reconstruct the speed of this boat ... because of the infinitely changing and number of variables," Group testified.

Group said that, because different law enforcement reports and 911 tapes listed several different departure times from Put-in-Bay, where Speer and Barnett embarked, he could not determine how fast he was going. Ohio Department of Natural Resources investigator Sam Dewalt had previously testified that Speer was likely going 39 mph.

Speer called 911 at about 2 a.m. to report his friend missing. Barnett's body was found the next day, Aug. 7, washed up on the shore of Mouse Island.

Although prosecutors argued that Speer pushed Barnett from the boat, they also presented evidence of his reckless driving, perhaps to give jurors the option of finding Speer guilty of one of the lesser charges.

Different law enforcement documents and statements made by Speer listed departure times of anywhere from 9 p.m. on Aug. 5 to 1:45 a.m. on Aug. 6. The drastic difference in departure would dramatically change the calculation of Speer's speed, Group said.

Group also said that Dewalt did not take the weight of the boat into account. Group used an analogy of pulling a small child in an inner tube through water, versus pulling a teen 10 years older through the water.

"I huff and puff and I can't tow her as fast because now that same inner tube is sitting deeper in the water with the same boat," he said. "The more heavily loaded a boat is, the more energy it will require, which will result in a decrease in speed."

Amber Foster, who keeps the accounting books for Speer at his plastics company, testified that the company did not owe money to Barnett on the day he died. Prosecutors presented evidence last week that the pair had argued over $10,000 in the days preceding Barnett's death.